System and method for apportioning storage

ABSTRACT

A computer-implemented method, computer program product and computing system for defining a cache storage portion within a cache storage device coupled to a computing device. An application storage portion is defined within the cache storage device coupled to the computing device. The cache storage portion is configured to store cache data and the application storage portion is configured to store application data.

CROSS-REFERENCE PARAGRAPH

The subject application is a continuation of U.S. patent applicationSer. No. 13/249,559, filed on Sep. 30, 2011. The entire content of theapplication is herein incorporated by reference.

TECHNICAL FIELD

This disclosure relates to cache memory systems and, more particularly,to enhanced functionality cache memory systems.

BACKGROUND

Storing and safeguarding electronic data is of paramount importance inmodern business. Accordingly, various systems may be employed to protectsuch electronic data.

The use of solid-state storage devices is increasing in popularity. Asolid state storage device is a data storage device that usessolid-state memory to store persistent data. A solid-state storagedevice may emulate (and therefore replace) a conventional hard diskdrive. Additionally/alternatively, a solid state storage device may beused within a cache memory system. With no moving parts, a solid-statestorage device largely eliminates (or greatly reduces) seek time,latency and other electromechanical delays and failures associated witha conventional hard disk drive.

SUMMARY OF DISCLOSURE

In a first implementation, a computer-implemented method includingdefining a cache storage portion within a cache storage device coupledto a computing device. An application storage portion is defined withinthe cache storage device coupled to the computing device. The cachestorage portion is configured to store cache data and the applicationstorage portion is configured to store application data.

One or more of the following features may be included. The cache datamay include cache user data. The cache data may include cache metadata.The cache storage portion may be configured to store cache data for astorage area network. The cache storage portion may be overprovisioned.The application storage portion may be mappable as a drive. The cachestorage device may include flash memory.

In another implementation, a computer program product resides on acomputer readable medium that has a plurality of instructions stored onit. When executed by a processor, the instructions cause the processorto perform operations including defining a cache storage portion withina cache storage device coupled to a computing device. An applicationstorage portion is defined within the cache storage device coupled tothe computing device. The cache storage portion is configured to storecache data and the application storage portion is configured to storeapplication data.

One or more of the following features may be included. The cache datamay include cache user data. The cache data may include cache metadata.The cache storage portion may be configured to store cache data for astorage area network. The cache storage portion may be overprovisioned.The application storage portion may be mappable as a drive. The cachestorage device may include flash memory.

In another implementation, a computing system includes a processor andmemory configured to perform operations including defining a cachestorage portion within a cache storage device coupled to a computingdevice. An application storage portion is defined within the cachestorage device coupled to the computing device. The cache storageportion is configured to store cache data and the application storageportion is configured to store application data.

One or more of the following features may be included. The cache datamay include cache user data. The cache data may include cache metadata.The cache storage portion may be configured to store cache data for astorage area network. The cache storage portion may be overprovisioned.The application storage portion may be mappable as a drive. The cachestorage device may include flash memory.

The details of one or more implementations are set forth in theaccompanying drawings and the description below. Other features andadvantages will become apparent from the description, the drawings, andthe claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic view of a storage network and a cache processcoupled to a distributed computing network;

FIG. 2 is a diagrammatic view of the storage network of FIG. 1;

FIG. 3 is a flowchart of the cache process of FIG. 1; and

FIG. 4 is a flowchart of the cache process of FIG. 1.

Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

System Overview:

As will be appreciated by one skilled in the art, the present disclosuremay be embodied as a method, system, or computer program product.Accordingly, the present disclosure may take the form of an entirelyhardware embodiment, an entirely software embodiment (includingfirmware, resident software, micro-code, etc.) or an embodimentcombining software and hardware aspects that may all generally bereferred to herein as a “circuit,” “module” or “system.” Furthermore,the present disclosure may take the form of a computer program producton a computer-usable storage medium having computer-usable program codeembodied in the medium.

Any suitable computer usable or computer readable medium may beutilized. The computer-usable or computer-readable medium may be, forexample but not limited to, an electronic, magnetic, optical,electromagnetic, infrared, or semiconductor system, apparatus, device,or propagation medium. More specific examples (a non-exhaustive list) ofthe computer-readable medium would include the following: an electricalconnection having one or more wires, a portable computer diskette, ahard disk, a random access memory (RAM), a read-only memory (ROM), anerasable programmable read-only memory (EPROM or Flash memory), anoptical fiber, a portable compact disc read-only memory (CD-ROM), anoptical storage device, a transmission media such as those supportingthe Internet or an intranet, or a magnetic storage device. Note that thecomputer-usable or computer-readable medium could even be paper oranother suitable medium upon which the program is printed, as theprogram can be electronically captured, via, for instance, opticalscanning of the paper or other medium, then compiled, interpreted, orotherwise processed in a suitable manner, if necessary, and then storedin a computer memory. In the context of this document, a computer-usableor computer-readable medium may be any medium that can contain, store,communicate, propagate, or transport the program for use by or inconnection with the instruction execution system, apparatus, or device.The computer-usable medium may include a propagated data signal with thecomputer-usable program code embodied therewith, either in baseband oras part of a carrier wave. The computer usable program code may betransmitted using any appropriate medium, including but not limited tothe Internet, wireline, optical fiber cable, RF, etc.

Computer program code for carrying out operations of the presentdisclosure may be written in an object oriented programming languagesuch as Java, Smalltalk, C++ or the like. However, the computer programcode for carrying out operations of the present disclosure may also bewritten in conventional procedural programming languages, such as the“C” programming language or similar programming languages. The programcode may execute entirely on the user's computer, partly on the user'scomputer, as a stand-alone software package, partly on the user'scomputer and partly on a remote computer or entirely on the remotecomputer or server. In the latter scenario, the remote computer may beconnected to the user's computer through a local area network (LAN) or awide area network (WAN), or the connection may be made to an externalcomputer (for example, through the Internet using an Internet ServiceProvider).

The present disclosure is described below with reference to flowchartillustrations and/or block diagrams of methods, apparatus (systems) andcomputer program products according to embodiments of the disclosure. Itwill be understood that each block of the flowchart illustrations and/orblock diagrams, and combinations of blocks in the flowchartillustrations and/or block diagrams, can be implemented by computerprogram instructions. These computer program instructions may beprovided to a processor of a general purpose computer, special purposecomputer, or other programmable data processing apparatus to produce amachine, such that the instructions, which execute via the processor ofthe computer or other programmable data processing apparatus, createmeans for implementing the functions/acts specified in the flowchartand/or block diagram block or blocks.

These computer program instructions may also be stored in acomputer-readable memory that can direct a computer or otherprogrammable data processing apparatus to function in a particularmanner, such that the instructions stored in the computer-readablememory produce an article of manufacture including instruction meanswhich implement the function/act specified in the flowchart and/or blockdiagram block or blocks.

The computer program instructions may also be loaded onto a computer orother programmable data processing apparatus to cause a series ofoperational steps to be performed on the computer or other programmableapparatus to produce a computer implemented process such that theinstructions which execute on the computer or other programmableapparatus provide steps for implementing the functions/acts specified inthe flowchart and/or block diagram block or blocks.

Referring to FIG. 1, there is shown cache process 10 that may reside onand may be executed by storage network 12, which may be connected tonetwork 14 (e.g., the Internet or a local area network). Storage network12 may include or may be a portion of one or more storage area networks(SAN). As will be discussed below in greater detail, a SAN may includeone or more of a personal computer, a server computer, a series ofserver computers, a mini computer, a mainframe computer, a RAID arrayand an NAS. The various components of storage network 12 may execute oneor more operating systems, examples of which may include but are notlimited to: Microsoft Windows XP Server™; Novell Netware™; RedhatLinux™, Unix, or a custom operating system, for example.

As will be discussed below in greater detail, cache process 10 maydefine a cache storage portion within a cache storage device coupled toa computing device. Cache process 10 may define an application storageportion within the cache storage device coupled to the computing device.The cache storage portion may be configured to store cache data and theapplication storage portion may be configured to store application data.

The instruction sets and subroutines of cache process 10, which may bestored on storage device 16 included within storage network 12, may beexecuted by one or more processors (not shown) and one or more memoryarchitectures (not shown) included within storage network 12. Storagedevice 16 may include but is not limited to: a hard disk drive; a flashdrive, a tape drive; an optical drive; a RAID array; a random accessmemory (RAM); and a read-only memory (ROM).

Network 14 may be connected to one or more secondary networks (e.g.,network 18), examples of which may include but are not limited to: alocal area network; a wide area network; or an intranet, for example.

Various data requests (e.g. data request 20) may be sent from clientapplications 22, 24, 26, 28 to storage network 12. Examples of datarequest 20 may include but are not limited to data write requests (i.e.a request that a data segment be written to storage network 12) and dataread requests (i.e. a request that a data segment be read from storagenetwork 12).

The instruction sets and subroutines of client applications 22, 24, 26,28, which may be stored on storage devices 30, 32, 34, 36 (respectively)coupled to client electronic devices 38, 40, 42, 44 (respectively), maybe executed by one or more processors (not shown) and one or more memoryarchitectures (not shown) incorporated into client electronic devices38, 40, 42, 44 (respectively). Storage devices 30, 32, 34, 36 mayinclude but are not limited to: hard disk drives; flash drives, tapedrives; optical drives; RAID arrays; random access memories (RAM); andread-only memories (ROM). Examples of client electronic devices 38, 40,42, 44 may include, but are not limited to, personal computer 38, laptopcomputer 40, personal digital assistant 42, notebook computer 44, aserver (not shown), a data-enabled, cellular telephone (not shown), anda dedicated network device (not shown).

Users 46, 48, 50, 52 may access storage network 12 directly throughnetwork 14 or through secondary network 18. Further, storage network 12may be connected to network 14 through secondary network 18, asillustrated with phantom link line 54.

The various client electronic devices may be directly or indirectlycoupled to network 14 (or network 18). For example, personal computer 38is shown directly coupled to network 14 via a hardwired networkconnection. Further, notebook computer 44 is shown directly coupled tonetwork 18 via a hardwired network connection. Laptop computer 40 isshown wirelessly coupled to network 14 via wireless communicationchannel 56 established between laptop computer 40 and wireless accesspoint (i.e., WAP) 58, which is shown directly coupled to network 14. WAP58 may be, for example, an IEEE 802.11a, 802.11b, 802.11g, Wi-Fi, and/orBluetooth device that is capable of establishing wireless communicationchannel 56 between laptop computer 40 and WAP 58. Personal digitalassistant 42 is shown wirelessly coupled to network 14 via wirelesscommunication channel 60 established between personal digital assistant42 and cellular network/bridge 62, which is shown directly coupled tonetwork 14.

As is known in the art, all of the IEEE 802.11x specifications may useEthernet protocol and carrier sense multiple access with collisionavoidance (i.e., CSMA/CA) for path sharing. The various 802.11xspecifications may use phase-shift keying (i.e., PSK) modulation orcomplementary code keying (i.e., CCK) modulation, for example. As isknown in the art, Bluetooth is a telecommunications industryspecification that allows e.g., mobile phones, computers, and personaldigital assistants to be interconnected using a short-range wirelessconnection.

Client electronic devices 38, 40, 42, 44 may each execute an operatingsystem, examples of which may include but are not limited to MicrosoftWindows™, Microsoft Windows CE™, Redhat Linux™, or a custom operatingsystem.

The Cache Process:

Referring also to FIG. 2, storage network 12 may include a virtualmachine layer (e.g. virtual machine layer 100) and a plurality ofstorage targets Ti-a (e.g. storage targets 102, 104, 106, 108). Storagetargets 102, 104, 106, 108 may be configured to provide various levelsof performance and/or high availability. For example, one or more ofstorage targets 102, 104, 106, 108 may be configured as a RAID 0 array,in which data is striped across storage targets. By striping data acrossa plurality of storage targets, improved performance may be realized.However, RAID 0 arrays do not provide a level of high availability.Additionally/alternatively, one or more of storage targets 102, 104,106, 108 may be configured as a RAID 1 array, in which data is mirroredbetween storage targets. By mirroring data between storage targets, alevel of high availability is achieved as multiple copies of the dataare stored within storage network 12.

While in this particular example, storage network 12 is shown to includefour storage targets (e.g. storage targets 102, 104, 106, 108), this isfor illustrative purposes only and is not intended to be a limitation ofthis disclosure. Specifically, the actual number of storage targets maybe increased or decreased depending upon e.g. the level ofredundancy/performance/capacity required.

As discussed above, storage network 12 may include or be a portion ofone or more SANs, wherein virtual machine layer 100 includes a pluralityof application servers that run network-based applications that areaccessed via client applications 22, 24, 26, 28. Examples of suchnetwork—based applications may include but are not limited to databaseapplications, document management applications, engineering designapplications, and email applications.

When storage network 12 is configured as a SAN, the various componentsof storage network 12 (e.g. virtual machine layer 100 and storagetargets 102, 104, 106, 108) may be coupled using network infrastructure110, examples of which may include but are not limited to a Layer 2network and a Layer 3 network.

As is known in the art, the data link layer is Layer 2 of theseven-layer OSI model as well as the five-layer TCP/IP model. Layer 2may respond to service requests from the network layer and may issueservice requests to the physical layer. Within a Layer 2 network,devices (e.g. the devices within virtual machine layer 100 and storagetargets 102, 104, 106, 108) may be addressed using MAC (i.e., MediaAccess Control) addresses. When network infrastructure 110 is a Layer 2network infrastructure, the devices within virtual machine layer 100 andstorage targets 102, 104, 106, 108 may have a unique MAC address.

Further and as is known in the art, the network layer is Layer 3 of theseven-layer OSI model as well as the five-layer TCP/IP model. Layer 3may respond to service requests from the transport layer and may issueservice requests to the data link layer. In the TCP/IP model, Layer 3may be referred to as the Internet layer. Within a Layer 3 network,devices (e.g. the devices within virtual machine layer 100 and storagetargets 102, 104, 106, 108) may be addressed using IP (i.e., InternetProtocol) addresses. When network infrastructure 110 is a Layer 3network infrastructure, each of the devices within virtual machine layer100 and storage targets 102, 104, 106, 108 may have a unique IP address.

Generally, the network layer (i.e., Layer 3) may be responsible forend-to-end (e.g., source to destination) data delivery, whereas the datalink layer (i.e., Layer 2) may be responsible for node-to-node (e.g.,hop to hop) data delivery.

Virtual machine layer 100 may execute all or a portion of cache process10. Additionally, one or more of storage targets 102, 104, 106, 108 mayexecute all or a portion of cache process 10. For example, cache process10 may be a multi-component process that includes e.g., a VM Layer-basedcomponent (not shown) and a target-based component (not shown). Forexample and for illustrative purposes, the VM Layer-based component ofcache process 10 may be executed on virtual machine layer 100. Furtherand for illustrative purposes, the target-based component of cacheprocess 10 may be executed on each of storage targets 102, 104, 106,108. Accordingly, the VM Layer-based component of cache process 10 andthe target-based component(s) of cache process 10 may cooperativelyoperate to effectuate all of the functionality of cache process 10.

The instruction sets and subroutines of the VM Layer-based component ofcache process 10, which may be stored on a storage device (e.g., storagedevice 16) coupled to virtual machine layer 100, may be executed by oneor more processors (not shown) and one or more memory architectures (notshown) included within virtual machine layer 100. Storage device 16 mayinclude but is not limited to: a hard disk drive; a tape drive; anoptical drive; a RAID array; a random access memory (RAM); and aread-only memory (ROM).

The instruction sets and subroutines of the target-based component ofcache process 10, which may be stored on a storage device (not shown)coupled to e.g., each of storage targets 102, 104, 106, 108 may beexecuted by one or more processors (not shown) and one or more memoryarchitectures (not shown) included within each of storage targets 102,104, 106, 108. The storage device (not shown) may include but is notlimited to: a hard disk drive; a flash drive; a tape drive; an opticaldrive; a RAID array; a random access memory (RAM); and a read-onlymemory (ROM).

Virtual machine layer 100 may include one or more virtual machines Vin(e.g., virtual machines 112, 114) and each of these virtual machines mayinclude one or more physical computing devices (e.g., server computers116, 118 for virtual machine 112 and server computers 120, 122 forvirtual machine 114). Each of these physical computing devices may havea storage device physically coupled to it. For example, server computer116 is shown to be coupled to storage device 124; server computer 118 isshown to be coupled to storage device 126; server computer 120 is shownto be coupled to storage device 128; and server computer 122 is shown tobe coupled to storage device 130. Examples of storage devices 124, 126,128, 130 may include but are not limited to: hard disk drives; flashdrives; tape drives; optical drives; RAID arrays; random access memories(RAM); and read-only memories (ROM).

As is known in the art, a virtual machine is a software implementationof a computing device that is configured to execute programs like aphysical machine. Virtual machines may be separated into two categories(based upon their use and degree of correspondence to any real machine),namely: a system virtual machine that is configured to provide acomplete system platform that supports the execution of a completeoperating system; and a process virtual machine that is configured toexecute a single program.

For illustrative purposes only and for one particular embodiment, assumethat storage devices 124, 126, 128, 130 are flash-based storage devicesthat are configured to function as cache devices for data that is beingstored to and/or retrieved from one or more of storage targets 102, 104,106, 108.

As storage network 12 is typically configured for high-availability,multiple virtual machines may be employed (e.g., virtual machines 112,114). Accordingly, during the normal course of operation of virtualmachine layer 100, certain virtual machines may need to be brought outof service and other virtual machines may need to be brought intoservice to replace those virtual machines that were brought out ofservice.

For illustrative purposes, assume that virtual machine 112 needs to bebrought down and, therefore, virtual machine 114 needs to be broughtinto service to perform the functionality that was previously beingperformed by virtual machine 112. As storage network 12 is configuredfor high availability, functional continuity is important. Accordingly,virtual machine 112 will typically not be shut down until virtualmachine 114 is up and performing the functionality that was previouslybeing handled by virtual machine 112. Accordingly, to a user (e.g.,users 46, 48, 50, 52) that is using one of the applications that isbeing executed on virtual machine 112, the transition from virtualmachine 112 to virtual machine 114 should be seamless and should gounnoticed by the user.

Continuing with the above-stated example in which virtual machine 112needs to be brought down and replaced by virtual machine 114, assume forillustrative purposes that only server computer 116 within virtualmachine 112 is operating (e.g., server computer 118 is configured forspare capacity). As discussed above and for this particular example,storage device 124 (which is coupled to server computer 116) isconfigured as a cache storage device for server computer 116.Accordingly, since storage device 124 is functioning as a cache storagedevice for server computer 116 included within virtual machine 116, inorder to have a successful transition from virtual machine 112 tovirtual machine 114, the content of storage device 124 should betransferred from storage device 124 to a storage device coupled to aserver computer included within the target virtual machine. In thisparticular example, the target virtual machine is virtual machine 114.For illustrative purposes, assume that server computer 120 includedwithin virtual machine 114 is the designated target computing device(i.e., to replace the functionality of server computer 116). Further,assume that the target storage device for the cache data currentlystored on storage device 124 is storage device 128 (which is coupled toserver computer 120 included within virtual machine 114).

As stated above, storage network 12 includes a plurality of storagetargets (e.g., storage targets 102, 104, 106, 108). In order to increasethe efficiency of the transfer of the cache data included within storagedevice 124 to storage device 128, an intermediary device (e.g., sharedstorage device 132) that has similar performance characteristics to thatof storage device 124 and storage device 128 may be utilized.Accordingly, if storage devices 124, 128 are flash storage devices (asthey are in this particular example), shared storage device 132 may alsobe a flash storage device.

The cache data stored within storage device 124 may include cache userdata and/or cache metadata. Cache user data may include the actual datasegments being stored within storage targets 102, 104, 106, 108.Examples of such cache user data may include but are not limited todatabase files, spreadsheet files, document files, etc. Cache metadatamay include data that locates and/or provides information concerning thecache user data. Examples of such cache metadata may include but are notlimited to data that locates the specific data segment within storagedevice 124, and data that provides information concerning the datasegment (e.g., author, edit time/date, expanded description, etc.).

Accordingly and referring also to FIG. 3, cache process 10 may move 200at least a portion of the cache data from storage device 124 coupled toserver computer 116 included within first virtual machine 112 (i.e., thevirtual machine to be shut down in this example) to shared storagedevice 132. Accordingly and for example, each piece of data storedwithin storage device 124 may be moved to shared storage device 132.Accordingly and at the end of this operation, storage device 124 may beempty and all of the cache data that was previously stored on storagedevice 124 may be located on shared storage device 132.

Once this operation is fully or partially complete, cache process 10 maybegin to move 202 the newly-relocated cache data from shared storagedevice 132 to (in this example) storage device 128 coupled to servercomputer 120 included within virtual machine 114 (i.e., the virtualmachine replacing virtual machine 112 in this example). Accordingly andfor example, each piece of data stored on shared storage device 132 maybe moved to storage device 128. Accordingly and at the end of thisoperation, shared storage device 132 may be empty and all of the cachedata that was previously stored on shared storage device 132 may belocated on storage device 128.

As discussed above, cache data may include cache user data and/or cachemetadata. Accordingly, the above-described operation carried out bycache process 10 may move 200, 202 cache user data and/or cachemetadata.

Alternatively, cache process 10 may be configured to directly move 204the above-described cache metadata from storage device 124 coupled toserver computer 116 included within virtual machine 112 to storagedevice 128 coupled to server computer 120 included within second virtualmachine 114. For example, the above-described cache metadata may bemoved 204 from storage device 124 to storage device 128 via a Layer 3procedure.

As discussed above and in the TCP/IP model, Layer 3 may be referred toas the Internet layer. Within a Layer 3 network, devices (e.g. thedevices within virtual machine layer 100 and storage targets 102, 104,106, 108) may be addressed using IP (i.e., Internet Protocol) addresses.When network infrastructure 110 is a Layer 3 network infrastructure,each of the devices within virtual machine layer 100 and storage targets102, 104, 106, 108 may have a unique IP address.

Once the above-described cache data movement procedures are effectuatedand the appropriate additional procedures are performed (e.g., startingup virtual machine 114 and the appropriate applications on computerserver 120), virtual machine 112 may be shut down. Accordingly, once thefunctionality of virtual machine 112 has been migrated to virtualmachine 114, virtual machine 114 for all intents and purposes hasessentially become virtual machine 112, as virtual machine 112 wasreplicated in virtual machine 114 and then virtual machine 112 was shutdown. Therefore and as discussed above, to a user (e.g., users 46, 48,50, 52) that is using one of the applications that is being executed onvirtual machine 112, the transition from virtual machine 112 to virtualmachine 114 would occur in the background and would be seamless gounnoticed by the user,

While storage devices 124, 126, 128, 130 are described above as beingflash-based storage devices that are configured to solely function ascache devices for data that is being stored to and/or retrieved from oneor more of storage targets 102, 104, 106, 108, other configurations arepossible and are consider to be within the scope of this disclosure.Further, while one or more of storage targets 102, 104, 106, 108 aredescribed above as being coupled of server computers that are includedwithin virtual machines, this is for illustrative purposes only and isnot intended to be a limitation of this disclosure. Accordingly and forthe following discussion, while storage targets 102, 104, 106, 108 arecoupled to server computers, the server computers to which they arecoupled need not be included within virtual machines and may be e.g.,stand alone application servers.

For example, cache process 10 may configure one or more of storagedevices 124, 126, 128, 130 (which may or may not be included within oneor more virtual machines) so that they function as both a cache deviceand an application storage device. Specifically and referring also toFIG. 4, cache process 10 may define 250 a cache storage portion within acache storage device (e.g., storage device 124) coupled to a computingdevice (e.g., server computer 116). Cache process 10 may also define 252an application storage portion within the cache storage device (e.g.,storage device 124) coupled to the computing device (e.g., servercomputer 116). Accordingly, if storage device 124 is a sixty-fourgigabyte flash storage device, cache process 10 may configure storagedevice 124 so that a first thirty-two gigabytes of the sixty fourgigabytes would be viewable and mappable as a disk drive usable by theapplications being executed on server computer 116 (i.e., theapplication storage portion) and the remaining thirty-two gigabytes ofthe sixty four gigabytes would be useable for the above-describedcaching services (i.e., the cache storage portion).

When e.g., storage device 124 is configured in this fashion by cacheprocess 10, the cache storage portion will be configured to cache datathat is stored to and/or retrieved from one or more of storage targets102, 104, 106, 108; while the application storage portion will beconfigured to store application data that is being used by one or moreof the applications being executed by e.g., server computer 116. Forexample, once an application storage portion is configured by cacheprocess 10, this application storage portion may be used to store a swapfile that is used by e.g., a database application being executed onserver computer 116.

When configuring the application storage portion of e.g., storage device124, the above-described application storage portion may beoverprovisioned, in that the actual size of the application storageportion defined 252 by cache process 10 may be smaller than the sizeidentified as being available to the application(s). Continuing with theabove-stated example, assume that storage device 124 is a sixty-fourgigabyte flash storage device. Further assume that cache process 10configures storage device 124 so that a first thirty-two gigabytes ofthe sixty-four gigabytes is viewable and mappable as a disk drive usableby the applications being executed on server computer 116 and theremaining thirty-two gigabytes of the sixty four gigabytes is useablefor the above-described caching services. Accordingly, cache process 10may overprovision the application storage portion so that it appearsthat e.g., forty-eight gigabytes of storage are available to theapplications on server computer 116. However, while only thirty-twogigabytes of storage are actually available within storage device 124for the application storage portion, in the event that the variousapplications being executed on server computer 116 use more than thethirty-two gigabytes of available storage space, cache process 10 maydynamically reduce the size of the cache storage portion so that amaximum application storage portion of forty-eight gigabytes of storagespace is available for the applications being executed on servercomputer 116.

As will be appreciated by one skilled in the art, the present disclosuremay be embodied as a method, system, or computer program product.Accordingly, the present disclosure may take the form of an entirelyhardware embodiment, an entirely software embodiment (includingfirmware, resident software, micro-code, etc.) or an embodimentcombining software and hardware aspects that may all generally bereferred to herein as a “circuit,” “module” or “system.” Furthermore,the present disclosure may take the form of a computer program producton a computer-usable storage medium having computer-usable program codeembodied in the medium.

The flowchart and block diagrams in the Figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods and computer program products according to variousembodiments of the present disclosure. In this regard, each block in theflowchart or block diagrams may represent a module, segment, or portionof code, which comprises one or more executable instructions forimplementing the specified logical function(s). It should also be notedthat, in some alternative implementations, the functions noted in theblock may occur out of the order noted in the figures. For example, twoblocks shown in succession may, in fact, be executed substantiallyconcurrently, or the blocks may sometimes be executed in the reverseorder, depending upon the functionality involved. It will also be notedthat each block of the block diagrams and/or flowchart illustration, andcombinations of blocks in the block diagrams and/or flowchartillustration, can be implemented by special purpose hardware-basedsystems that perform the specified functions or acts, or combinations ofspecial purpose hardware and computer instructions.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the disclosure.As used herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof.

The corresponding structures, materials, acts, and equivalents of allmeans or step plus function elements in the claims below are intended toinclude any structure, material, or act for performing the function incombination with other claimed elements as specifically claimed. Thedescription of the present disclosure has been presented for purposes ofillustration and description, but is not intended to be exhaustive orlimited to the disclosure in the form disclosed. Many modifications andvariations will be apparent to those of ordinary skill in the artwithout departing from the scope and spirit of the disclosure. Theembodiment was chosen and described in order to best explain theprinciples of the disclosure and the practical application, and toenable others of ordinary skill in the art to understand the disclosurefor various embodiments with various modifications as are suited to theparticular use contemplated.

Having thus described the disclosure of the present application indetail and by reference to embodiments thereof, it will be apparent thatmodifications and variations are possible without departing from thescope of the disclosure defined in the appended claims.

What is claimed is:
 1. A computer-implemented method comprising:defining a cache storage portion within a first cache storage devicecoupled to a first computing device and a second cache storage devicecoupled to a second computing device, wherein the cache storage portionis for storing cache data, wherein the cache data includes cache userdata and cache metadata; and moving the cache data from the first cachestorage device coupled to the first computing device to the second cachestorage device coupled to the second computing device, wherein the cacheuser data is moved via a shared intermediate flash storage device whilethe cache metadata is moved directly from the first cache storage devicewithin the first virtual machine to the second cache storage devicewithin the second virtual machine.
 2. The computer-implemented method ofclaim 1 wherein the cache storage portion is overprovisioned.
 3. Thecomputer-implemented method of claim 1 wherein the cache storage portionis for storing cache data for a storage area network, wherein the cachedata is at least one of: stored to and retrieved from one or morestorage targets included within the storage area network.
 4. Thecomputer-implemented method of claim 1 wherein the cache data is locatedin one or more virtual machines.
 5. The computer-implemented method ofclaim 1 further comprising defining an application storage portionwithin the cache storage device coupled to the computing device.
 6. Thecomputer-implemented method of claim 5 wherein the application storageportion is mappable as a drive.
 7. The computer-implemented method ofclaim 1 wherein the first and second cache storage devices include flashmemory.
 8. A computer program product residing on a non-transitorycomputer readable medium having a plurality of instructions storedthereon which, when executed by a processor, cause the processor toperform operations comprising: defining a cache storage portion within afirst cache storage device coupled to a first computing device and asecond cache storage device coupled to a second computing device,wherein the cache storage portion is for storing cache data, wherein thecache data includes cache user data and cache metadata; and moving thecache data from the first cache storage device coupled to the firstcomputing device to the second cache storage device coupled to thesecond computing device, wherein the cache user data is moved via ashared intermediate flash storage device while the cache metadata ismoved directly from the first cache storage device within the firstvirtual machine to the second cache storage device within the secondvirtual machine.
 9. The computer program product of claim 8 wherein thecache storage portion is overprovisioned.
 10. The computer programproduct of claim 8 wherein the cache storage portion is for storingcache data for a storage area network, wherein the cache data is atleast one of: stored to and retrieved from one or more storage targetsincluded within the storage area network.
 11. The computer program ofclaim 8 wherein the cache data is located in one or more virtualmachines.
 12. The computer product of claim 8 further comprisingdefining an application storage portion within the cache storage devicecoupled to the computing device.
 13. The computer program product ofclaim 12 wherein the application storage portion is mappable as a drive.14. The computer program product of claim 8 wherein the first and secondcache storage devices include flash memory.
 15. A computing systemcomprising: at least one processor device; and at least one memoryarchitecture coupled with the at least one processor device; wherein theat least one processor device is further configured to performoperations comprising; defining a cache storage portion within a firstcache storage device coupled to a first computing device and a secondcache storage device coupled to a second computing device, wherein thecache storage portion is for storing cache data, wherein the cache dataincludes cache user data and cache metadata; and moving the cache datafrom the first cache storage device coupled to the first computingdevice to the second cache storage device coupled to the secondcomputing device, wherein the cache user data is moved via a sharedintermediate flash storage device while the cache metadata is moveddirectly from the first cache storage device within the first virtualmachine to the second cache storage device within the second virtualmachine.
 16. The computer system of claim 15 wherein the cache storageportion is overprovisioned.
 17. The computer system of claim 15 whereinthe cache storage portion is for storing cache data for a storage areanetwork, wherein the cache data is at least one of: stored to andretrieved from one or more storage targets included within the storagearea network.
 18. The computer system of claim 15 wherein the cache datais located in one or more virtual machines.
 19. The computing system ofclaim 15 further comprising defining an application storage portionwithin the cache storage device coupled to the computing device, whereinthe application storage portion is mappable as a drive.
 20. Thecomputing system of claim 15 wherein the first and second cache storagedevices include flash memory.